Chain-drill.



G. 0-. LEOPOLDQ CHAIN DRILL.

APPLIOATION FILED 00T.11, 1911.

Patented July 30, 1912.

2 SHEETS-SHEET 2.

WWW f UNITED STATES PATENT OFFICE. n

GEORGE O. LEOPOLD, 0F PHILADELPHIA, PENN$YLVANIA, ASSIGNOR TO NORTH BROSMFG (70., OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYL-VANIA.

CHAIN-DRILL.

Application filed October 11, 1911. Serial No. 654,114.

To all whom it may concern:

Be it known that I, GEORGE O. Lnoronn, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented certainImprovements in Chain-Drills, of which the following is a specification.

The main object of this invention is to improve the construction ofdrilling 'lTlQOllZL- nisms in which a chain or its equivalent is used tohold the work to the drill, so that, on rotating the mechanism, thedrill will be automatically fed to the work.

A further object of the invention is to provide means whereby the drillor other tool can be quickly adjusted to the work after the device isattached to the work by the chain.

The invention can be applied either to an ordinary brace, or to a breastdrill, as desired.

In the accompanying drawings :-Figure 1, is a side view of the improvedchain drill arranged to be used in connection with a brace; Fig. 2, is aview looking in the direction of the arrow, Fig. 1; Fig. 3, is avertical sectional view on the line 3-3, Fig. 2; Fig. 1, is a sectionalplan view on the line 4-4, Fig. 1; Fig. 5, is a perspective View of thechain grip; Fig. 6, is a perspective view of the spindle, showing thecam detached therefrom; Fig. 7, is an enlarged sectional plan view onthe line 77, Fig. 8; Fig. 8, is a sectional view on the line 8-8, Fig. 7Fig. 9, is a view in elevation, showing the invention applied to abreast drill; Fig. 10, is a sectional plan view on the line 10-40, Fig.9; Fig. 11, is a sectional view on the line 1111, Fig. 10; and Fig. 12,is a perspective view of the chain grip illustrated in Fig. 9.

Referring in the first instance to Figs. 1 to 8, inclusive, B is aspindle having at one end a chuck B and at the opposite end, in thepresent instance, a quadrangular tapered shank 5 adapted to fit thesocket of a brace or other driver. A is a carrier mounted loosely on thespindle and held between a cam 72 and a collar 6 Depending from thecarrier A is a pin 0 on which is mounted a pawl piece D carry ing aspring pawl d which engages a ratchet wheel 6 on the end of the hollowscrew stem E which is mounted on the spindle B. This screw stem is heldbetween the cam Z) and a Specification of Letters Patent.

Patented July so, 1912.

collar f on the spindle B, and this collar inturn rests on a shoulder.Between this collar and the end of the screw stem are balls f, whichform a ball thrust bearing. The lower portion of the spindle is enlargedas indicated in Fig. 3, and is threaded for the reception of the chuckB.

Arranged to slide on the pin 0 is a chain grip head H having a screwthreaded opening it for the passage of the threaded stem E. On each sideof the grip head are notched arms arranged to engage the links of achain of any suitable type. The chain is passed around the work andsecured to the grip head in the ordinary manner.

By the above construction the grip head H can be moved intermittently byturning the spindle, as the cam b rests in an opening (5 in the pawlpieceD and vibrates the pawl piece on its pin 0 as the cam rotates. Thismovement causes the pawl to feed the at a time, feeding the tool carriedby the chuck to its work as it cuts the hole.

The pawl'ci is mounted in the pawl piece so that it can be turned tofeed right or left and the teeth of the ratchet wheel are madeaccordingly.

In order to quickly adjust the tool to the work after the chain has beenapplied, I attach the cam directly to the ratchet wheel by a slipconnection, so that when the cam is turned it will carry the ratchetwheel with it, moving the hollow screw stem down to the work and, whenthe tool is in contact with the work, the slip connection will'allow thecam to turn independently of the ratchet wheel, and then the ratchetwheel will be fed forward through the medium of the pawl and the pawlpiece.

In the present instance, as clearly shown in Figs. 6, 7 and 8, I securethe cam b to the spindle B by a key 8 adapted to a key way 8 in thespindle, and in the cam is a socket c in which is mounted a pin 6, andback of the pin is a spring 25. The outer end of the pin is rounded andin the upper side of the ratchet wheel 6 are rounded cavities 0, two inthe present instance, into which the pin is projected by the spring.

Under normal conditions the ratchet wheel will be driven directly by thecam through this pin '1, but, as before stated, when the tool reachesthe work the friction will be sufiicient to cause the cam to moveindependently of the sprocket wheel; the pin being forced back due tothe resistance of the work, and then, as the tool cuts its way into thework, it will be fed forward through the medium of the pawl piece I) andpawl (Z.

In Figs. 9 to 12, inclusive, I have shown the invention applied to abreast drill, in which A is a carrier in the form of a frame havingbearings for the spindle B carrying a chuck at its lower end. On thespindle are two bevel pinions M, M, one fast and the other loose in thepresent instance, and meshing with the bevel pinions is a gear wheel athaving a handle m. The loose pinion M acts as a balance wheel to preventthe straining of the large driving gear wheel m. D is a pawl piecepivotally mounted on the pin 0, F ig. 11, and 6Z2 is a pawl whichengagesthe ratchet wheel 6 on the screw stem E, on which is mounted thechain grip head H having arms to engage the chain, as shown in Figs. 9and 12.

The pawl piece D has an opening similar to theo'p'ening in the pawlpiece D, for the reception of the cam 72 on the spindle B By the aboveconstruction it will be seen that I am enabled to manufacture a verysimple and effective breast drill of few parts, and in which the toolwill be positively fed to the work, and in which the tool can be readilyadjusted to the work after being clamped thereto.

I claim The combination in a chain drill, of a spindle; means forturning said spindle; a screw stem; a ratchet wheel secured to saidstem; a carrier having a pin; a pawl piece pivotally mounted on said pinand spanning the spindle; a pawl mounted in the pawl piece and engagingthe ratchet wheel; a cam secured to the spindle and arranged to actuatethe pawl piece; with a slip connection between the spindle and theratchet wheel.

2. The combination of a spindle; means for turning the spindle; acarrier in which the spindle is mounted; said carrier having a pin atone side of .the spindle; a screw stem on the spindle; a ratchet wheelsecured to the stem; a pawl piece mounted on the pin of the carrier andspanning the spindle; a cam secured to the spindle and located betweenthe arms of the pawl piece; a pawl on the pawl piece engaging theratchet: wheel; a grip head having a threaded opening engaging the screwstem; and a chain engaging the head and adapted to pass around the work.

3. The combination of a spindle; a carrier in which the spindle ismounted; a pin projecting from the carrier; a pawl piece pivot-allymounted on the pin and spanning the spindle; a cam secured to thespindle and located within the pawl piece so that as the cam is turnedthe pawl piece will be actuated; a screw stem mounted on the spindle; aratchet wheel secured to the screw stem; a pawl on the pawl piecearranged to engage the ratchet wheel, said ratchet wheel having a recessin one face; a pin mounted in the cam and arranged to couple the camdirectly to the ratchet wheel so that the ratchet wheel and its screwstem will turn with the cam and its spindle until the resistance issufficient to cause the pin to slip out of the recess, when the screwstem will be turned through the medium of the pawl and ratchet.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

GEORGE O. LEOPOLD.

Copies of this patent may he obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

